Generators - info in general and pics of some wave forms

[Dan_69GTX]

This is more of an informational post to explain various differences in generators what I looked at before purchasing one. Consumers Reports (CR) just did a review and I greatly disagree with what they picked as a "best buy" - a Generac GP5500. Following are things I considered before making my purchase.



CR covered these and I looked at as well:

- reliability

- voltage variation - old gen sets can vary a LOT!

- included features that you have to pay extra for. (some electric start models do not include a battery).



CR didn't cover:

- How clean is the power (sine wave). Is it safe for sensitive electronics?

- Frequency output - how close to 60Hz is it and does it maintain 60Hz throughout it's load range? The Generac XG8000E was 62Hz.

- How loud is it? Most state what the db is - make sure you read from what distance they measured! Generac didn't give any info - called their support - they don't give it out - period.

- How long can it operate at max load? Ex: I found the Honda site says 30 minutes at max load. I haven't seen this info from other manufactures. I even called several manufacures directly and non would state exact time. Several did say "only said a few seconds".

- How available are parts, service, service manuals, etc. I called Champion and they don't have a manual for the one I was looking at. Generac will allow the dealer to sell you one. Up to the dealer for price and if they will sell it to you.

- How easy is it to maintain? Ex: Reading the manuals for several Generacs you have to remove the gas tank and side panel to replace the battery.

- Does the battery get charged while the generator is running or does it require a separate charger? Many don't charge the battery - the more expensive ones do.

- Can it produce 120/240V AND can you set it to produce the full load for just 120V (useful for camping). Mostly seen on more expensive gen sets. Remember that a 5000W 120/240V unit puts out 2500W per side - for a total of 5000W. This means any 120V device can NOT exceed 2500W!



I'm sure there are other questions, but these are some that I've been looking into.



Here is MY opinion based upon what I found.



Honda seems to be the standard others compare themselves to. All Chinese knockoffs I've seen copy them.



Honda: expensive, good power output, reliable, easy to get parts for, owners manuals online - free, service manuals online or ebay (yes, they have their own ebay account), GREAT resell value.

Yamaha: similar to Honda, called MFG and they will not say how long you can run above rated but below max wattage. Parts and owners manual online - free, service manual online.

Champion - cheap! Can't get service or parts manuals - I called them to try and get one. Basically a copy of a Honda.

Generac - middle of the road, does have some dumb designs to make maintenance a hassle.



Here are some wave forms from gen sets I had access to.

 

[Dan_69GTX]

Here are a few more pics of wave forms.

 

[Dan_69GTX]

I've got a few more to test and will post pics of what their wave forms look like. I also will test a few inverters I have access to.

So, if anyone has any other pics of wave forms, I'd love to see them here. If you have or know of a generator that is still running at XX number of hours or that seemed to die prematurely at XX hours - I'd love to know that too! This type of info would help us all in our purchasing decisions and to know what's best for our situation.

I forgot to mention that the EU2000 and EU6500 both stayed around 60 Hz (+/- . 08) when testing with a load. Inverters are VERY good at keeping the frequency stable. The other Gens (non inverters) did fluctuate more - but for them frequency is dependent on engine speed. They were +/- 3Hz.

 

[Wertles]

Great information. I have a Honda EU3000iS and couldn't be happier. He's, they are expensive but when I can use the running generator as a cup holder while reading a book (yes, that quiet and smooth) it is worth it. It goes forever on a tank of gas and will power the entire camper, AC included (I never run the water heater on electric). I have a 8500 watt Generac for the house, it is loud, it sometimes is finicky to start but it hasnt let me down yet. For as often as I need it and use it, it was a good value.

 

[Road Dog]

One think you didn't mention is floating neutral vs bonded neutral which matters if you're hooking up to a house via a transfer switch.

(A bonded neutral means the neutral (white wire) is connected to the frame (ground) on the generator. )

 

[Shadrach]

When I am at the campgrounds and I hear a generator running I will quite often go for a walk and see if I can see it to find out what make it is. A lot of times it is hidden from sight, as most of the time I camp in Provincial campgrounds with lots of trees. The noisier ones are usually painted yellow. I am curious to see what each brand sounds like in real life situations. For portables Honda and Yamaha seem to be the quietest. Onan did have a portable for a while and I have used them, a 1700 and a 3200. They are no longer sold by Cummins but were actually Robin/Subaru models.

For me a 150 lb genset is too heavy to lift out of my truck by myself so when I have borrowed my buddies 3200 I just leave it on the tailgate and run it there. Being up a little higher does make it noisier though. Even thought it will make my travel trailer longer I plan on adding an Onan Micoite/Microquiet "built in" to my back bumper rack. It will be a 3600 and powered by propane as I don't need to carry a third fuel. I carry 2 spare 30# bottles anyway. Thanks for the test data. Shad

 

[Bill Stockard]

I have a 8500 watt Generac for the house, it is loud, it sometimes is finicky to start but it hasnt let me down yet. For as often as I need it and use it, it was a good value.

I have a 12-year old Generac 4000XL portable generator that I use for limited house backup. It never fails to start on the second pull of the recoil starter rope. I use Sta-bil fuel additive and non-ethanol gasoline in it and I turn the fuel off allowing the carb to run dry when shutting it down. The longest power outage I've run it was for 56 hours in below freezing temperatures and it never missed a beat.



Bill

 

[jelag]

Dan

I'd like to thank you for posting this... I've not seen a full sine wave off a gen set on a scope in years... Used to sell automotive tune up equipment years ago and have put a lot of stuff up on the scope...

I did purchase an inverter and found that it wouldn't power the heated mattress pad in the RV and an email to and a call from the engineer who designed the thing told me that I needed a full sine wave inverter because of the chips in the controller... Who would have thought that a simple heated pad would have such an need... the engineer directed me to donrowe.com in Monroe OR for the best price and quality... The first unit had too dirty of a sine wave for the controller to work... . the one from DonRowe has functioned exceptionally well (read, keeps the wife warm) for the past 4 or 5 years as well as power the TV and Direct TV receiver when we're out of range of shore power...

I have an older, louder Honda 5K watt unit. . so I'm waiting to see what you post... Again thanks. .

 

[Dan_69GTX]

Thanks for the comments!



jelag, If you have a way of posting a pic of the wave form of the Honda, I'd love to see it. I haven't found one around here I can scope yet. I did find a couple other gen sets that I will test. I also was able to test a CyberPower inverter from Best Buy. It is just a really BAD square wave.



Here is another gen - it's a Coleman 1850 sport. It is about 10 years old.

 

[gtoli]

Wow, great pics and info. I'm no electrical engineer, but it looks yo my untrained eye that the Honda gensets are the best so far.

Gene

 

[gtoli]

Wow, great pics and info. I'm no electrical engineer, but it looks yo my untrained eye that the Honda gensets are the best so far.



Gene

 

[slowneasy]

Dan, thanks for the pictures and information... that's what you call "a picture is worth a thousand words"! I'll be following this thread, I have a Onan genset in the horse trailer and have always been satisfied with it. It's a gas unit, I think 3600 model. It's reasonably quiet, okay, it is really quiet however if I could complain about one thing is the exhaust is down near ground level (right behind the rear tire, street side) and that is on the same side as the RV door. So you get a dose of exhaust once in a while. I'd still like to have one of those smaller Honda gensets too.

 

[BIGNASTY]

Yamaha Gen it was the quietest (dont know now) but hate to hear someone fire up one that sounds like your at a construction site. Cant beat this IMO had it sense 04 and just change oil before every camping season change air filter and a plug 1 time each.

Inverter EF3000iSE/B

 

[Dan_69GTX]

Here are some pics of waveforms from a Black and decker inverter PI100AEB. It is a 100W inverter.

 

[VZarich]

Outstanding thread gentlemen. Lets see some more waveforms added as time goes on. This thread illustrates to me very clearly exactly why the Honda inverter generators are worth the extra money other than that they are economical and long lasting.

 

[TGentry]

Yamaha EF2000iS:

Oscilloscope measurement's captured on a Tektronix 2246 with a TEK P6109 100MHZ 10X 10M Ohm 11. 8pF to 14. 8pF 300VRMS passive probe. Probe's ground connected to one of the ground pins on one of the two NEMA 5-15 receptacles on the unit, and probe's tip on the smaller of the two straight blades.

120VAC mains measurement test setup check:
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Here are some photos for Yamaha EF2000iS output:
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Other Yamaha EF2000iS output measurement methods:
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[EricBu12]

How about the Onan 5000w Gold Marquis? I have that on my 5th.

 

[Dan_69GTX]

Hey TGentry. Thanks for those waveforms.

Do you have pics you could post along with the video. Makes comparison easier especially if someone wants to print it off and show other people.

Thanks!

 

[TGentry]

Hey TGentry. Thanks for those waveforms.



Do you have pics you could post along with the video. Makes comparison easier especially if someone wants to print it off and show other people.



Thanks!

Hi Dan_69GTX,



Updated original post with photos. Do these measurements look reasonable to you?

 

[TGentry]

Schumacher Model PI-750 :: 750 Watt Power Inverter:

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